This invention relates to spatulas for taking cell samples from the body for histological examination, especially for use in taking samples for analysis in screening for cervical cancer.
Spatulas for gynecological cytology and cervical cancer screening are conventionally made from wood and typically comprise an elongate body portion and a head portion shaped that includes a side lobe. Spatulas having this type of construction are often referred to by those with skill in the art as xe2x80x9cAylesbury Spatulas.xe2x80x9d The spatula is used to sample cells at the transformation zone, which may be invisible to the naked eye, between the columnar and squamous epithelium of the uterine cervix, which is also commonly referred to as the squamo-columnar junction, where precancerous changes are most likely to occur. Where the transformation zone is visible, the spatula can be rotated through 360 degrees around the cervix, to sample the transformation zone. Where the transformation zone is within the cervical canal, the endocervix may be similarly sampled so as to maximize the collection of a useful cell sample.
In use, more specifically, the spatula is inserted in the vagina so that the head portion contacts the cervix and the body portion is then rotated about its longitudinal axis so that an inner edge of the side lobe of the head portion scrapes around the exterior wall of the cervix, removing therefrom a sample of cells. Conventionally, the sample is then transferred to a glass slide to provide a xe2x80x9csmearxe2x80x9d for histological examination by microscope. However such examination is necessarily subjective and therefore potentially unreliable and, indeed, the technique has occasionally given rise to publicly expressed concerns regarding the effectiveness of screening programs in some hospitals. In any event, the act of transferring the sample to the slide involves subjecting the sample to shearing forces, which can physically damage or distort the cells, making interpretation of results more difficult.
In an attempt to avoid the problems of manual analysis, apparatus for automated examination by so-called liquid base cytology has more recently been developed. In use, the sample from the spatula is added to a liquid to form a suspension of cells and it has been found that the results of the ensuing examination are far more consistently reliable than with manual examination. However, a disadvantage is that the wooden spatula tends to absorb the liquid, resulting in difficulty in obtaining complete transfer of the sample to the liquid and a consequential weak or dilute liquid-base sample for cytological analysis.
Accordingly, what has been needed but heretofore unavailable is a spatula of the type described that can be used for obtaining samples both for manual and automated analysis but which especially overcomes the problems of wooden spatulas when the samples are analyzed by liquid base cytology and which reduces or eliminates the likelihood of damage to the sample.
The present invention meets these and other needs without adding any complexity, inefficiencies, or significant costs to procurement and use of cell sampling spatulas. The various embodiments, modifications, and variations of the present invention disclosed herein are readily adapted for ease of manufacture, low fabrication costs, and immediate compatibility with both the cell sampling and examination techniques presently in use and prospective techniques not yet developed or established.
In its most general sense the present invention overcomes the shortcomings of the prior art in any of a number of generally effective configurations. According to one aspect of the present invention, a spatula for taking cell samples for histological examination includes a body portion and a head portion, in which the spatula is formed from a non-absorbent plastics material and includes a frangible zone between the body and neck portions whereby the head portion can be broken away from the body portion by relative bending about a lateral axis in the frangible zone, the frangible zone nevertheless having sufficient strength to resist fracture under rotational forces about the longitudinal axis of the spatula in use. Preferably, the plastic material may be sterilized for applications requiring a contamination free examination environment.
The surface of the spatula, which is conventionally of a generally flat configuration, or at least of the head portion thereof, and preferably is formed to have a surface texture that is adapted to capture and retain sample cells. The surface texture may include, for example without limitation, stippled, dimpled, satin-effect, or roughened surfaces, or any combination thereof.
The frangible zone may comprise any structural feature which provides a weakness in terms of relative bending resistance between the head and body portions about a lateral axis in the frangible zone while not significantly compromising the rotational strength as between the head and body portions under twisting forces about the longitudinal axis of the spatula. The frangible zone may comprise a lateral groove or channel between the head and body portions on one or preferably both sides of the spatula.
Preferably, the channel or each groove is closed-ended in that it does not extend to the edges of the spatula and optionally the groove is provided with one or more intermediately-located fillets or webs to moderate the weakness. Where a groove is formed on each side of the spatula, they preferably coincide on respective sides whereby the lateral axis of weakness passes through the bridging material forming a common base to and extending between the respective grooves. The fillets are preferably alternately disposed in such respective grooves.
A suitable plastics material for formation of spatulas according to the invention is preferably a thermoplastic material that can include, for example, acetal resins, delrin, fluorocarbons, polyesters, polyester elastomers, polyolefins, metallocenes, polyamides, nylon, polyvinyl chloride, polybutadienes, silicone resins, acrylontrile-butadiene-styrene plastics (ABS), polypropylene, liquid crystal polymers, combinations ard mixtures and composites thereof, and reinforced combinations and mixtures and composites thereof.
For functional and economic reasons, the thickness of the spatulas should be preferably within the range of about 1.0 mm to 4.0 mm (millimeters), and more preferably between about 1.5 mm and 2.5 mm, and more preferably about 2.0 mm. The groove or grooves should extend in depth to approximately two thirds of the thickness in aggregate, especially where they are coincident on respective sides. Should the grooves be included only on a single side or be disposed in an offset relationship, their aggregate depth could be greater, for example up to 1.5 times the thickness of the material.
Spatulas according to the invention may also have an enlarged tail portion remote from the head portion, shaped for example as an oval, and such tail portion may likewise be formed with a frangible zone and be adapted for uses similar to that of the head portion.
These variations, modifications, and alterations of the various preferred embodiments may be used either alone or in combination with one another as will become more readily apparent to those with skill in the art with reference to the following detailed description of the preferred embodiments and the accompanying figures and drawings.